Answer: b) Malignant hyperthermiaMALIGNANT HYPERTHERMIADrug- or stress-induced hypermetabolic syndrome.Vigorous muscle contractions, an abrupt increase in temperature, subsequent cardiovascular collapseUncontrolled release of Ca2+ from the sarcoplasmic reticulum due to defect in the ryanodine receptor (RYR1) is the initiating eventInherited as autosomal dominant fashion, with variable penetrance & expressivity.Triggers: Stress, excitement, anoxia, viral infections, lymphoma, ischemia or hypoxia.Early signs: masseter muscle contracture, muscle rigidity, metabolic acidosis, sinus tachycardia, supraventricular tachyarrhythmias, mottling or cyanosis of the skin, increased CO2 production, and hypertension.Two signs helpful in making a prehyperthermic diagnosisIncreased end-tidal CO2Masseter spasmM/C with combination of depolarizing blocking agent and anesthetic.Drugs known to trigger malignant hyperthermiaDrugs safe in malignant hyperthermia* Halothane* Methoxyflurane* Enflurane, isoflurane* Succinylcholine* Decamethonium* Gallamine* Diethyl ether,* Ethylene, Ethyl chloride* Trichloroethylene* Ketamine* Phencyclidine* Cyclopropane* Nitrous oxide* Barbiturates* Diazepam* Tubocurarine* Pancuronium, vecuronium* OpiatesManagement of Malignant HyperthermiaDiscontinue volatile anesthetic and succinylcholine.Hyperventilate with 100% O2 at high flows.Administer sodium bicarbonate, 1-2 mEq/kg intravenously.Mix dantrolene sodium with sterile distilled water and administer 2.5 mg/kg ivInstitute cooling measures (lavage, cooling blanket, cold intravenous solutions).Administer additional doses of dantrolene if needed.Treat severe hyperkalemia with dextrose, 25-50 g IV, and regular insulin, 10-20 U intravenously (adult dose).